Process and apparatus for manufacturing monofilaments



F. SCRAGG Dec. 15, 1964 PROCESS AND APPARATUS FOR MANUFACTURING MONOFILAMENTS 2 Sheets-Shee'rI l Filed Dec. 5, 1961 Dec. 15, 1964 PROCESS AND Filed Dec. 5, 1961 F. SCRAGG APPARATUS FOR MANUFACTURING MONOFILAMENTS 2 Sheets-Sheet 2 United States Patent Office 3,161,708 Patented Dec. 15, 1964 The present invention relates to synthetic yarns, particularly textile iibers of continuous synthetic lilamentary p form.

It has long been known that textile yarns can be produced fsynthetically by extruding a suitable lamenti forming material from a solution or melt and solidifying the resulting filaments which are usually later twisted lightly'to form a yarn of continuous filaments. Such a yarn has certain disadvantages compared with yarn made from staple fibers, and various Vattempts have been made to overcome these disadvantages. Thus for example, a yarn made from staple liber is essential-ly twisted in order t0 hold the fibers together. As a result, the yarn so produced has relatively little elastic extension so that it can readily be used for weaving. Again, the yarn possesses bulk not only by virtue of the fact that all the libe-rs are of slightly diderent shapes and therefore repel one another by mechanical pressure, but also because the ends of the fibers often protrude from the yarn, thus giving it a soft springy handle.

Various attempts have been made to modify the. shape of the filaments of which a continuous filament yarn is composed to simulate these two properties. Thus the bulk and soft handle have been simulated by imparting to each filament of an artificial continuous filament yarn a series of distortions of more or less random character so that the yarn itself becomes of large diameter and of soft handle. Such yarns however inevitably have a minimum of some elastic extension and this extension limits not only the use of the` yarns but the mechanical stresses to which they may be subjected during manufacture of cloth therefrom. Again in connection with yarns of this character, it is found that since the. filaments themselves are not broken, but extend angularly to the a'xis of the yarn in a series of curls or loops, the resulting yarn is apt to catch on the lingers of handlers of the yarn thus initiating pilling.

It would of course be possible, as already has been done, to cut up continuous filament yarns, form them into sliver and spin the sliverj This however is a lengthy and expensive process, and the resultant yarn is not always as satisfactory as that made from natural libers owing to the smooth surface of the artificial filaments and the need for applying a high degree of twist to hold them firmly in the yarn.

One of the objects of the present invention is to provide a process and apparatus for continuously manufacturning yarn which will closely approach the properties of natural yarn.

Another object of the present invention is to provide a process wherein the yarn is cut from an extrusion and wherein the cutting may take place either directly after the extrusion or at a much later time after the material has been extruded and stored.

Still another object of the present invention is to provide a process and apparatus which is simple and inexpensive and which is capable of continuously producing any -desired number of synthetic yarns from a single extrusion.

of plastic having fins and continuously cutting from the sheet a yarn which has branches formed by the cut fins. The apparatus of the invention includes as extruding means capable of extruding a plastic sheet having integral lins and a rotary cutter means which cuts through the plastic sheet and fins to form the branched ilamentary yarn of the invention.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together" with additional objects and advantages thereof, will be best understood from the following description of specic embodiments when read in connection with the accompanying drawings, in which:

FIG. l is a diagrammatic sectional side elevation of one possible embodiment of an apparatus according to` the i invention;

FIG. 2 is a fragmentary end view of the extruder nozzle of FIG. 1;

FIG. 3 is a fragmentary perspective illustration of the manner in which the yarn is out from the extrusion formed with the structure of FIGS. 1 and 2;

FIG. 4 is a partly sectional diagrammatic side elevation of another embodiment of an apparatus according to the invention;

FlG. 5 is a fragmentary perspective illustration of one of the nozzle-forming members of the extruder of FIG. 4;

FIG. 6 fragmentarily illustrates part of the yarn formed with the process and apparatus of FIGS. 4 and 5;

FlG. 7 is a diagrammatic, partly sectional side elevation of a further embodiment of an apparatus according to the invention; and

FIG.4 8 is a fragmentary developed view of the structure of FIG, 7.

Referring to FIG. l there is shown therein an extruder including the outer housing 41 to which material to be extruded is fed through the conduit4la. The outer housing 41 fixedly carries a circular extruder nozzle member 41h. As is shown in FIG. 2, the member 41b is formed along its inner periphery with axially extending notches 42. The extruder includes an inner, axially bored mernber 41C having afree cylindrical end portion 41d (FIG. 2) which is surrounded by the member 411) and spaced therefrom as indicated in FIG. 2. Thus, there will be extruded from the nozzle of the extruder a hollow cylindrical plastic sheet having a plurality of elongated axial fins projecting radially therefrom and formed integrally therewith.

The hollow bore of the inner extruder member 41e carries bearings which support for rotation a shaft 44 xedly carrying a rotary cutter 43 and driven by a motor 45 through a suitable belt-and-pulley drive as shown diagrammatically in FIG. l. The cutter 43 may be in the form of a simple elongated blade have diametrically opposed cutting portions extending across the outlet of the extruder nozzle. Thus, with this embodiment as the extrusion issues from the extruder a pair of monofilaments will be simultaneously cut therefrom along a spiral formed by the axial advance of the cylindrical extrusion with respect to the rotary cutting means. This action is illustrated in FlG. 3 where an end of the cutting blade 43 is shown cutting through the extrusion as it issues from the extruder nozzle so as to form the monoilament 50 which will of course have integral filament branches formed by the cutting action of the blade 43 as it passes through the fins. Any suitable rotary take-up means is proivded to take up the filaments continuously as they are cut from the extrusion and to form packages therefrom.

alegres In theembodiment shown in FIG. 4 the extruder includes a screw which forces the plasitc extrusion material through the extruder nozzle. In this case the nozzle includes a pair of rings which are xedly carried coaxially by the extruder in slightly spaced relation and each of these rings is formed with a plurality of radial notches extending to the inner periphery of the ring. The housing portion 51a shown in FIG. 4 has a cylindrical portion on which both of the extiuder nozzle rings are lixedly nounted in slightly spaced relation, and this cylindrical Jortion of the housing Sla is hollow and closed at its left and, as viewed in FIG. 4. Thelcylindrical portion of the liousing 51a is formed in alignment with the gap between `:he pair of extruder nozzle rings 51 with a plurality of cirz'umferentially spaced openings so that the plastic extrusion material will be forced radially through these openngs and into the space between the pair of nozzle rings 51 as well as into the radial notches 52 thereof. The radial iotches 52 (FIG. 5) of both rings are identical and are iirected toward each other so that the plastic material which lills the entire space between the rings 51 as well ts the notches 52 thereof, due to the resistance of the novement of the plastic 'material out of the nozzle, issues n the form of a flat sheet which is constantly increasing in liameter and which has fins formed integrally on its op- ).osed faces. A rotary cutter 53 extends axially along the :xterior periphery of the nozzle rings 51 and lis driven tbout the axis of the extruder through a drive as shown liagrammatically in FIG. 4. Thus, as the finned extruiion sheet issues from the extruder the rotary cutter 53 vill cut circumferentially through thesheet to form a ilament having integral branches as shown in FIG. 6. )f course, more than one cutting blade may be connected :o the drive to rotate simultaneously so as to form simulaneously a plurality of filaments which through any suitible take-up means are wound into packages.

The extrusion formed bythe embodiment of FIGS. 1 1nd 2 need not be'cut simultaneously with the'issuance )f the extrusion from the extruder. Instead any desired engths of the extrusion may be stored away in flattened :ondition When it is desired to cut the hollow, finned )lastic cylinder into the yarn of the invention, the apiaratus shown in FIGS. 7 and 8 is used. This apparatus ncludes a hollow metal cylinder 60 ixedly connected at ts interior to a spider 6l which is fixed at its central porion to a stationary shaft 62 which is in turn fixed at its eft end, as viewed in FIG.' 7, toany suitable supporting 'rame 63. The shaft 62 passes through a hollow shaft 64 vhich is freely rotatable on the shaft 62 and is prevented rom moving axially thereon by any suitabile collars or he like. The rotary hollow shaft 64 ixedly carries withn the cylinder 60 a friction roller 65. This friction roller i frictionally engages with its outer periphery a plurality f feed rollers 66 each of which is carried by a shaft 67 upported for rotation by brackets 68 fixed to and locatd in the interior of the cylinder 60. .As is shown most learly in FIG. 8, the cylinder 60 is formed with a pluality of circumferentially arranged slots 69 through which he feed rollers 66 project slightly beyond the exterior urface of the cylinder 60. As is apparent from FIG. 8 he axes of the several feed rollers 66 are slightly skewed Vith respect to the cylinder axis and the direction of roation of the feed rollers 66 is such that when they engage he inner surface of the plastic cylinder which is slipped nto the cylinder 60, at its right end, as viewed in FIG. 7, nd which is shifted to the left, as viewed in FIG. 7, only 'ne plastic cylinder passes over the feed rollers 66, then he continuously rotating feed rollers 66 will continue he axial advance of the plastic cylinder to the left, as iewed in FIG. 7, along the cylinder 60.

The hollow shaft 64 xedly carries a cutter 43 which ray be identical with the cutter 4?, and in addition the ollow shraft 64 iixedly carries a gear itl which meshes lith a gear 7l driven by a motor 72. Thus, with this arthan 250 C., the temperature may be as high as 500 F rangement the plastic cylinder formed by the extrusion apparatus of FlGS. 1 and 2 is slipped onto the cylinder 60 and is then capable of being axially advanced toward the rotary cutter 43 which cuts through the cylindrical sheet and the fins projecting therethrough to form a filament in exactly the sam-e way as shown in FIG. 3.

It will be noted that since the friction roller 65 rotates in a direction opposite to that of each feed roller 66 the cutter 43 which rotates with the feed roller 65 opposes any tendency of the feed rollers 66 to rotate the plastic cylinder so that it is only advanced axially.

0f course, with the embodiment of FIG. 1 or the embodiment of FIG. 4 it is possible to maintain the cutting means stationary and to rotate the extrusion die.

The larnents produced according to the invention may be passed through ardye vat immediately after production, or the filaments may be wound and subsequently dyed. In any case a drawing operation, as described above, is applied to the yarn after it is cut, so as to in* crease its strength. Also, the filaments after drawing may, if desired, be twisted together to form multi-filament yarns.

In the case where the plastic material is cut with the structure of FIGS. 7 and 8 it is possible to dye the plastic material immediately after its extrusion before it has been cut into a lilarnent, and since the molecular arrangement is random in the undrawn extruded material it readily absorbs dye, so that the material may be dyed before being rolled for storage or slit. Also, if desired, the drawing operation may take place on the cylinder as it leaves the extruded dye and immediately after cooling. j

The branches formed on the trunk of the filament may have a length as great as or at least twice as'great as the average diameter of the trunk, and these branches may in fact have a length of live times, and preferably at least ten times, the average trunk diameter.

The plastic material extruded may bevany thermoplastic filament-forming or fiber-forming plastic and is also applicable to all other synthetic fibers such as viscose and the regenerated celluloses in general including also cellulose acetate. This process is also applicable to Orlon which is a polyacrylonitrile. Any suitable solvent for the plastic may be used, such as formic acid, cresol and phenol in the case of nylon, dimethylformamide in the case of Orlon, chloroform in the case of vinyon. In the case of regenerated cellulose, it is best to proceed as it comes from the manufacturer, i.e. extruded in the form of the xanthate and to spray the extrusion with a precipi# tating solution, for example of 10% sulfuric acid and 20% sodium sulfate.

In the case of cellulose diacetate the same is extruded in molten condition at a temperature somewhat greater 's using a heated grid at the throat of the press itself, just before the die. It may be cooled by means of air or rings which are water cooled. The diacetate is squeezed into the nozzle by means of a screw press in the form of powder.

The diacetate may also be used in the form of a very thick solution in acetone, the solution then being dried by means of warm `air yat a temperature of about 134 F.

Cellulose triacetate may be extruded in molten condition at a temperature of 570-580 F., or it may be extruded in the form of a solution thereof in methylene chloride in which `case the solvent is evaporated by means of dry air yat a temperature of F.

Nylon may be treated in the same manner as cellular diacetate, eg. by squeezing the powder in through a screw press and melting at the throat of the press'itself just before the die by means of a heated grid. The temperature may be about Z50-285 C. depending on the nature of the material. kThe cooling may be accomplished by a water cooled ring or by an air blast.

Terylene or Daeron may be treated in the same manner as nylon using a temperature of about 480 F.

Acrylan and Orlon may be treated in the form of a sticky solution thereof in dimethyl formamide which softens the acrylan or Orion and then dried by air at a temperature of about 150 F.

Rhovyl which is polyvinyl chloride is used in the form of a solution thereof in acetone or by melting at a temperature of about 365 F.

Polypropylene is used by melting at a temperature somewhat greater than 330 F.

The particular temperature and/ or solvent may be determined for any particular plastic from the handbooks which are available or by simple pretesting. `ln general the temperature chosen should be controlled within rather close limits to avoid damage to the plastic.

lt will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of yarn differing from the types described above.

While the invention has been illustrated and described as embodied in synthetic yarns, it is not intended to be limited to the details shown, since various modications and structural changes may be made Without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A process for manufacturing a monofilament having a continuous filament trunk and a plurality of filament branches formed integrally therewith, comprising the steps of continuously extruding, by means of an extruder, a plastic sheet having integral fins projecting therefrom, and continuously cutting the sheet and fins in a direction extending across said fins during issue of the sheet from the extruder, so as to form a monolament,

' 2. A process for manufacturing a monofilament having a continuous filament trunk and a plurality of integral filament branches, comprising the steps of continuously extruding, any means of extruder a hollow plastic cylinder having integral fins extending longitudinally thereof and projecting radially therefrom; and continuously rotating about the axis of the cylinder a cutting blade which circumferentially cuts the cylinder and fins as they issue from the extruder, so as to form a monofilament.

3. A process for manufacturing a monolament having a continuous filament trunk and a plurality of filament branches integral therewith, comprising the steps of continuously extruding, by means of an extruder, an annular sheet which increases in diameter during extrusion thereof and which has fins projecting from at least one of its side faces; and circumferentially cutting the sheet in a direction extending across the fins thereof as it issues from the cxtruder to form the monolament from the extruded sheet.

4. A process for manufacturing a monofilament having a continuous filament trunk and a plurality of integral filarnent branches, comprising .the steps of placing a tube of plastic material, having integral fins at its outer surface projecting substantially radially therefrom and extending substantially longitudinally thereof, on a substantially rigid cylinder; feeding the tube of plastic longitudinally of said cylinder so that the tube of plastic continuously moves beyond one end of said cylinder; and circumferentially cutting through the tube of plastic and the fins thereof in the region of said one end of said cylinder as the tube of plastic moves beyond said one end of said cylinder so as to continuously lform from the tube of plastic a branched monoiilarnent.

5. A process as recited in claim 4 and wherein the tube of plastic with said integral tins thereof are first extruded and dyed before being placed on said cylinder.

6. The process of claim 4 and wherein the plastic tube and fins thereof are first extruded and drawn before being placed on said cylinder.

7. A process for manufacturing a monofilament having a continuous filament trunk and a plurality of filament branches formed integrally therewith, comprising the step of cutting a plastic sheet having integral ns projecting from at least one face thereof and all extending up to and terminating at an edge of the sheet, along a path closely adjacent to and extending along said edge of said sheet and completely through the sheet and across the fins thereof so as to separate from the sheet a monolament having a continuous filament trunk and a plurality of filament branches formed integrally therewith.

8. Apparatus for manufacturing a monolarnent having a continuous trunk and branches extending integrally therefrom, comprising, in combination, extruding means for extruding a hollow plastic cylinder having fins projecting integrally therefrom, said extruding means having a nozzle from which said cylinder and fins issue; and rotary cutter means located adjacent said nozzle for cutting through the cylinder and fins as they issue from the nozzle, so as to form the monofilament.

9. Apparatus for manufacturing a monofilament having a continuous trunk and a plurality of branches integral therewith comprising, in combination, extruding means for radially extruding a sheet of plastic which continuously increases in area during extrusion thereof and which has fins at at least one of its side faces, said extruding means having a nozzle from which said sheet and fins issue; and rotary cutter means located adjacent said nozzle for circumferentially cutting through the sheet of plastic and the fins during issue thereof from said nozzle, so as to form the monofilament.

References (lite-d in the file of this patent UNITED STATES PATENTS 2,026,754 Stafford Ian. 7, 1936 2,082,744 Shaw June l, 1937 2,293,178 Stocker Aug. 18, 1942 2,333,267 Modigliani Nov. 2, 1943 2,377,908 Slaughter .lune l2, 1945 2,683,896 Patterson July 20, 1954 2,728,950 Annesser Ian. 3, 1956 2,808,617 Terrancini et al c.. Oct. 8, 1957 2,809,393 Hauptman Oct. 15, 1957 2,943,356 Rasmussen July 5, 1960 

1. A PROCESS FOR MANUFACTURING A MONOFILAMENT HAVING A CONTINOUS FILAMENT TRUNK AND A PLURALITY OF FILAMENT BRANCHES FORMED INTEGRALLY THEREWITH, COMPRISING THE STEPS OF CONTINOUSLY EXTRUDING, BY MEANS OF AN EXTRUDER, A PLASTIC SHEET HAVING INTEGRAL FINS PROJECTING THEREFROM, AND CONTINOUSLY CUTTING THE SHEET AND FINS IN A DIRECTION EXTENDING ACROSS SAID FINS DURING ISSUE OF THE SHEET FROM THE EXTRUDER, SO AS TO FORM A MONOFILAMENT. 